This invention relates to devices for towing automobiles and other motor vehicles and, in particular, to tow bar blocks which are positioned on a tow bar to support the vehicle while it is being towed.
In recent years, automobile manufacturers have recommended various measures be taken when towing vehicles to prevent the tow equipment from damaging the automobile body or finish. These measures are particularly important in cars made from lightweight material or cars having aerodynamic spoilers or air dams which can easily be damaged by such equipment during towing.
One measure recommended is to use a tow bar which consists of an elongated four-by-four wooden timber with two inverted U-shaped wooden tow blocks slidably mounted on the timber. The blocks are constructed so that they present a flat surface on the top of the inverted U. The tow bar arrangement described above is used with a standard sling-type crossbar towing device. The tow bar is positioned between the sling and the automobile undercarriage with the flat surfaces of the spacer blocks oriented upwardly to support the automobile. The spacer blocks are positioned to engage support elements on the underside of the car provided by the manufacturer to bear the weight of the car during towing. If the tow bar assembly were not used, the lightweight aerodynamic spoilers, bumpers or air dams of some cars would have to bear much of the vehicle's weight during towing which, of course, these parts were not designed to do.
Different cars have differently configured towing support elements. A flat surfaced tow block is not always satisfactory. The tow blocks can slip from or damage the support elements. The wooden tow blocks can also split if they are subjected even to moderate impact forces over time. If the blocks split or shift, the vehicle can shift while being towed such that the parts of the vehicle not designed to bear the weight of the vehicle are forced to do so, causing damage to the vehicle. Lastly, the wooden blocks are quite rigid and do not provide significant cushioning between the vehicle and the tow bar. The resulting shocks transmitted to the vehicle through the wooden tow bar blocks may damage the car, too.